1. Field of the Invention
The present invention relates to a network device that is connected to and communicates with a network, a network device control method, software program, and storage medium.
2. Description of the Related Art
In order to enhance the ease of use of network devices in the process of network communications, there have been proposed systems in which each network device registers, on a DNS server, a combination of the device's own IP addresses and host names identifying itself. Thus, a proposal aimed at improving the ease of use by registering a combination of IP addresses and host names on a DNS server has been disclosed, for instance, in Japanese Patent Laid-Open No. 2004-350133, which is described below. In the invention disclosed in this document, a second network device that intends to communicate with a first network device only needs to consider the host name of the first network device. Specifying host names for the first network devices makes it possible to acquire the IP addresses of the first network devices from the DNS server and initiate communication using the IP addresses.
However, the conventional technology did not allow users to select the IP addresses registered by network devices on a DNS server. Thus, all the IP addresses belonging to a network device were registered on the DNS server and mapped to host names.
It is contemplated that in the future the spread of IPv6 (Internet Protocol version 6) will lead to an environment in which a single network device will have multiple IP addresses. In such a case, the need to map all the IPv6 addresses the device has to host names will not necessarily arise.
For instance, IPv6 link-local addresses are not suitable for use in wide area networks (WANs). Accordingly, users are sometimes reluctant to permit access to their IPv6 link-local addresses. Nevertheless, if an IPv6 link-local address is mapped to a host name, the IPv6 link-local address may sometimes be acquired when another network device uses the host name to acquire IP addresses. As a result, other network devices end up attempting to access the network device using the IPv6 link-local address.
Furthermore, it is contemplated that in the future security technology will develop and operation will sometimes be carried out in such a manner that a part of communications will be disconnected. For example, when communication utilizing a specific IP address is disconnected, if a communication partner acquires the specific IP address from the DNS server and attempts to establish communication using that specific IP address, unnecessary processing is carried out. Namely, notwithstanding the attempts at communication with the IP address resolved from the host name, the packets will end up being discarded.